Have you shot an RX7? I am in the same boat, I’ve had the RX1 since it came out but I think I’m going to upgrade to the RX7 if I can get a deal on one.
The XV strings are a new blend closer to the newer BCY 454 material while the high octane strings are 452x like others mentioned. I just bought my first set of gas strings and went with the high octane set and it seems like a great string so far